1. Field of the Invention
This invention relates to a machine for applying cement coating to rubber tires and, more particularly, the invention is directed to a machine for applying cement to tires during the process of recapping.
The process of recapping worn tires comprises the steps of first removing the worn tread by means of a cutting device and removing any remaining tread with a buffing mechanism which further smooths the crown portion of the tire which receives the recap. A cap of rubber strip material is then cemented in place over the buffed and smooth crown of the tire, and the tire is vulcanized with the cemented cap in place. The present invention relates specifically to a machine for applying the cement which joins the cap to the tire.
Improvements in the recapping operation have previously involved designing cement applying machines which will apply the proper amount of cement to the buffed tire. However, the cement applying step performed with tire recapping machines generally in use is an operation which is inefficient in utilization of time, labor, and material. Furthermore, the operation of such tire recapping machines does not meet the stricter environmental regulations for the health and safety of the individual worker as usually the buffing and cementing steps are performed in the open. Accordingly, while tire recapping machines have been developed which satisfactorily apply the proper amount of cement to the buffed tire, there is still a great need for a cement applying machine in a tire recapping process which can meet the current standards for environmental health and safety and which will be significantly more efficient in the utilization of time and labor.
2. Description of the Prior Art
Prior cement applying devices for coating tires during the tire recapping process have attempted to increase the uniformity of application of the cement onto the crown of the buffed tire. U.S. Pat. No. 2,758,037, issued Aug. 7, 1956, to Cahill, is a typical example of a prior art device which has been designed to apply a thin film of cement uniformly over the cap-receiving surface of the tire supported on a rotating mandrel and yet will result in a great saving of time, material and labor. Typical of the cement applying device similar to the Cahill apparatus is that the application of the cement is done in the open wherein the cement fumes and excess spray fills the workplace area. Further, such devices do not automatically support tires of varying diameter and therefore must be manually adjusted each time that the size changes. U.S. Pat. No. 2,690,207, issued Sept. 28, 1954, to Godfrey, discloses a tire tread cementing machine in which a brush is utilized to supply cement to a rotating tire in which both the upper and lower beads of the tire are supported by moving support means. The tire is further mounted on a frame which can be adjusted so as to allow the various bead contacting means to support tires of varying diameter. However, as in the previously mentioned prior devices, the Godfrey machine cannot automatically adjust for tires of varying sizes and accordingly, manual labor must be utilized to prepare the cementing machine for tires of different sizes. U.S. Pat. No. 1,876,967, issued Sept. 13, 1932, to Krause et al, discloses a machine for painting tires in which the tire is clamped onto a pair of tire arms and rotated thereon, the painting application being accomplished within a casing in which the tire rotates. There is no disclosure in this patent that the casing is provided with a vent to remove excess fumes therefrom, nor is there a disclosure of an automatic means to adjust for tires of varying size. Accordingly, while prior art cement applying machines for tire recapping have successfully been structured so as to provide a uniform layer of cement on the buffed tire surface, such devices pose a significant health and safety hazard for those operating the machines and still require a significant amount of manual labor in order to manipulate the devices in order to accommodate all types of tires and tire sizes.